When attempting to register via register_web it throws the log I've pasted below and returns "Captcha API error" on the iframe. Unsure what could have caused this, all that changed was an upgrade from Debian 9, to 10. The configuration and API keys remain the same.
Example registration page: https://xmpp.is/account/register/xmpp_co/
Example log:
Aug 14 02:21:25 xmpp.co:register_web warn Unable to decode response from recaptcha: [0] certificate-chain-invalid

Hi Zash,
Thanks for the details. Must have been a recent change on Google's end then? I thought it was something that changed Lua-wise when upgrading to Debian 10. Coincidence that it broke then.
Is the issue being worked on? I could start a bug bounty.